Grape Juice Clarification by Filtration1

Abstract

It appears that pressure filtration of grape juice under the most efficient combination of conditions is about 25% more costly than vacuum precoat filtration (referring to juice only). However, this disadvantage might be offset somewhat by using the pressure filter in a winery for filtering wine at various steps during the ten months it is not being used for filtering juice. While the vacuum filter can be used for other purposes, it is not as versatile as the pressure filter. For the best economy, juice should be treated with an enzyme preparation and filtered at as high a temperature as is consistent with good practice and quality of the end product. Where elevated temperatures are not desired, enzyme-treated juice may be refrigerated (35-40°F) and warmed to room temperature at the time of filtration. Adequate filter area should be used for best economy. Filters too small can cause excessive filteraid costs, and filters that are too large increase overhead.

The data in this paper apply to one juice under specified conditions. A plant intending to filter juice should either run tests or have them run to determine optimum filter size. It would appear that most juices can be filtered at a cost near one cent per gallon.